With rapid development in electronic technologies, enhancement in computer and peripheral products performance and more powerful while lower-priced software tools continuously hitting the market, these products have become popular commodities in daily lives. Take the digital camera market for example, to attract a good-sized of new consuming group, manufacturers not only diligently develop potent new models, but also bundle image processing software with their camera products. By installing and running the software on a computer, a user can view or edit images captured earlier with a digital camera. This not only help save cost on developing films but also offer a variety of editing and design capabilities on the images.
Despite the numerous image editing functions offered by image processing software available on the market, the thirst for a function providing fast and effective foreground/background separation of images remains unquenched. With conventional image processing software installed on a computer, a user is capable of opening a digital image, selecting a desirable tool (e.g. an eraser, a pen or a pair of scissors) from a tool box available in said software and editing the foreground and background objects in said digital image. If an object in the foreground is all the user prefers to keep, he can select the scissors tool and by controlling a mouse and looking at the computer display screen, gradually cut along the outline of said object until it is ultimately extracted from said image. However, in the case where said foreground object possesses a complex shape, a user can easily cut into said object due too fluctuation in handling a mouse. Although an undo function is available to the user, once it is performed, previously cut line is completely discarded, meaning all effort is wasted. The user must start from ground zero and cut from the very beginning again. In addition to highly discouraging a user from doing foreground extraction, repetitive cutting and undoing seriously deteriorates the effectiveness and quality of foreground editing. Consequently, most users stay away from such a conventional editing method of this sort.
To address this issue, a number of manufacturers developed extraction tools. For example, the Photoshop image processing software by Adobe Systems Incorporated provides tools such as magic wand, lasso, eraser and filters. Handling these tools, however, can be a complicate task for beginners and without a significant period of training and practicing, it is usually difficult for a user to master the skills required. Another company Corel Corporation offers extraction software called Corel Knockout which is capable of separating a foreground object with fine edge details (e.g. feather, animal fur, shadow, hair strands, smoke and transparent materials) from a background and paste said extracted object onto another desired background. Despite the amazing effect, a user does need to precisely depict the inner edge and outer edge at the outline of a foreground object to accomplish the result. The difficulty of the task increases exponentially when the foreground object has plenty of angles or protruding parts. Tremendous time and effort is required in order to be able to extract an object of this nature.
To solve the above-mentioned drawbacks, Microsoft Corporation developed an extraction tool called Lazy Snapping. A user makes a few strokes of drawing on the foreground and background of an image and then the software intelligently extract the foreground from the background. Adobe Systems incorporated also include a specialized function called Magic Extract in their Photoshop Element 4.0 image processing software for easy separation of a foreground object from a background. While the above two software programs offer a more convenience extraction procedure, they are still lagging in providing a tool with easily operations and real-time results.
Therefore, facilitating a tool with intelligent functions so that users can extract a foreground object by simply applying a few pen strokes on the foreground and background of an image has become a goal in research and development of most manufacturers. With such a tool, long hours of training and practice can be spared while the separation remains accurate at the boundary where mutual penetration of foreground and background takes place to produce a realistic and precise extraction of a foreground object.